CN117413405A

CN117413405A - Heat transfer system with heat transfer fluid comprising liquid component and gas component

Info

Publication number: CN117413405A
Application number: CN202280038719.7A
Authority: CN
Inventors: P·基托; S·V·菲利普
Original assignee: Castrol Ltd
Current assignee: Castrol Ltd
Priority date: 2021-03-29
Filing date: 2022-03-25
Publication date: 2024-01-16
Also published as: KR20230163508A; EP4068470A1; JP2024511638A; WO2022208266A1

Abstract

A heat transfer system includes an electrochemical cell, a fluid circulation system, and a pump. The fluid circulation system includes a heat exchange section in thermal contact with the electrochemical cell. A cooling medium is disposed in the fluid circulation system and, at least within the heat exchange section of the fluid circulation system, the cooling medium comprises a mixture having a liquid component and a gaseous component.

Description

Heat transfer system with heat transfer fluid comprising liquid component and gas component

Background

Various electrochemical cells (such as batteries) are used to provide power to electrical devices when needed. Similar to other electrochemical cells, most batteries will generate heat when current is delivered to or drawn from the battery. If the generated heat is not dissipated, the battery will rise in temperature. Batteries typically have an effective operating temperature range and, if the battery exceeds a maximum operating temperature, the battery may become ineffective or even fail. In some cases, after a slight rise in temperature, the battery may be able to dissipate heat to its surroundings through a simple heat sink or without any thermal management. In other cases, a more specific heat transfer system is required to dissipate the heat generated by the battery.

Many heat transfer systems circulate a fluid to cool heat generating components. These systems can be complex and cumbersome. Thus, it may be particularly important to perform thermal management of heat generating components using an efficient heat transfer system.

Disclosure of Invention

Aspects of the invention are recited in the independent claims and preferred features are recited in the dependent claims.

These and other aspects, advantages, and alternatives will become apparent to those of ordinary skill in the art upon reading the following detailed description.

Drawings

The accompanying drawings are included to provide a further understanding of the systems and methods of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings are not necessarily to scale and the dimensions of the various elements may be distorted for clarity. The drawings illustrate one or more embodiments of the present disclosure and, together with the description, serve to explain the principles and operations of the disclosure.

FIG. 1 is a schematic plan view of a heat transfer system according to an embodiment of the present disclosure;

FIG. 2 is a schematic plan view of an electrochemical cell according to an embodiment of the present disclosure;

FIG. 3 is a schematic plan view of an electrochemical cell according to another embodiment of the present disclosure;

FIG. 4 is a schematic plan view of a heat transfer system according to another embodiment of the present disclosure;

FIG. 5 is a schematic plan view of a heat transfer system according to another embodiment of the present disclosure;

FIG. 6 is a schematic plan view of a heat transfer system according to yet another embodiment of the present disclosure;

FIG. 7 is a schematic plan view of a heat transfer system according to yet another embodiment of the present disclosure; and

fig. 8 is a flow chart of a method according to an embodiment of the present disclosure.

Detailed Description

Systems and methods for thermal management of electrochemical cells are disclosed herein. Advantageously, the systems and methods utilize a cooling medium that includes a liquid component and a gaseous component.

Thus, in a first aspect, the present disclosure provides a heat transfer system comprising:

an electrochemical cell comprising an electrochemical cell;

a fluid circulation system comprising a heat exchange section in thermal contact with the electrochemical cell;

a cooling medium disposed in the fluid circulation system, wherein, within the heat exchange section of the fluid circulation system, the cooling medium comprises a mixture comprising a liquid component and a gaseous component; and

a pump configured to circulate a cooling medium through the fluid circulation system.

In some embodiments of the heat transfer system, the gas component forms at least 50% by volume of the cooling medium within the heat exchange section of the fluid circulation system.

In some embodiments of the heat transfer system, at least a portion of the liquid component and the gas component of the cooling medium form a foam within the heat exchange section of the fluid circulation system.

In some embodiments of the heat transfer system, the heat exchange section of the fluid circulation system includes a fluid path that extends through the electrochemical cell such that the cooling medium is in direct contact with the electrochemical cell.

In some embodiments of the heat transfer system, the liquid component of the cooling medium includes at least one of a surfactant and a foam inhibitor.

In some embodiments of the heat transfer system, the fluid circulation system comprises:

a main circuit comprising a heat exchange section, wherein the liquid component of the cooling medium is confined to the main circuit,

a gas inlet in the main circuit upstream of the heat exchange section; and

a gas outlet in the main circuit downstream of the heat exchange section.

In some embodiments of the heat transfer system, the gas inlet is one of a plurality of gas inlets disposed upstream of the heat exchange section.

In some embodiments of the heat transfer system, the gas inlet is disposed below the electrochemical cell and the gas outlet is disposed above the electrochemical cell such that buoyancy of the gas component causes the gas component to rise through the electrochemical cell.

In some embodiments of the heat transfer system, the fluid circulation system further comprises a secondary loop extending from the gas outlet to the gas inlet for recirculating the gas component around the fluid circulation system.

In some embodiments of the heat transfer system, the cooling medium includes a liquid component and a gas component throughout the fluid circulation system.

In some embodiments of the heat transfer system, the pump is configured to circulate the liquid component and the gaseous component of the cooling medium as a mixture around the fluid circulation system.

In some embodiments of the heat transfer system, further comprising a mixer configured to promote bubble formation within the cooling medium.

In another aspect, the present disclosure provides a method of cooling an electrochemical cell, the method comprising:

providing a heat exchange section of a fluid circulation system in thermal contact with an electrochemical cell comprising an electrochemical cell; and

Circulating a cooling medium through the fluid circulation system to transfer energy from the electrochemical cell to the cooling medium, wherein the cooling medium comprises a liquid component and a gas component within a heat transfer section of the fluid circulation system.

In some embodiments of the method, circulating the cooling medium maintains the gaseous component of the cooling medium in a ratio of at least 50% by volume within the heat exchange section of the fluid circulation system.

In some embodiments of the method, circulating the cooling medium includes maintaining the cooling medium in the form of foam throughout the fluid circulation system.

In some embodiments of the method, circulating the cooling medium includes delivering the foam by pumping the foam.

In some embodiments of the method, the fluid circulation system comprises a main circuit, the main circuit comprising a heat exchange section,

wherein the liquid component of the cooling medium is limited to the main circuit and,

wherein circulating the cooling medium comprises injecting a gaseous component into the main circuit.

In some embodiments of the method, injecting the gaseous component into the main circuit drives the liquid component through the fluid circulation system.

In some embodiments of the method, the gas component is injected into the main circuit at a location below the electrochemical cell such that buoyancy of the gas component causes the gas component to rise through the electrochemical cell.

In some embodiments, the method further comprises collecting the gas component through an outlet of the main circuit.

Example systems and methods are described herein. It should be understood that the words "example" and "exemplary" are used herein to mean "serving as an example, instance, or illustration. Any embodiment or feature described herein as "example" or "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or features. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, like numerals typically identify like components unless context dictates otherwise. Other embodiments may be utilized, and other changes may be made, without departing from the scope of the subject matter presented herein.

The example embodiments described herein are not intended to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

As used herein, "about" means +/-5% with respect to measurement.

Unless otherwise indicated, the terms "first," "second," and the like are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Furthermore, references to items such as "second" do not require or exclude the presence of items such as "first" or lower numbered items and/or items such as "third" or higher numbered items.

Reference herein to "one embodiment" or "one example" means that one or more features, structures, or characteristics described in connection with the example are included in at least one embodiment. The phrase "one embodiment" or "an example" in various places in the specification may or may not refer to the same example.

As used herein, a system, device, apparatus, structure, article, element, component, or hardware that is "configured to" perform a specified function is actually able to perform that specified function without any change and is not merely a potential for performing that specified function after further modification. In other words, a system, device, structure, article, element, component, or hardware "configured to" perform a specified function is specifically selected, created, implemented, utilized, programmed, and/or designed for the purpose of performing that specified function. As used herein, "configured to" refers to an existing characteristic of a system, device, structure, article, element, component, or hardware that enables the system, device, structure, article, component, or hardware to perform a specified function without further modification. For the purposes of this disclosure, a system, device, structure, article, element, component, or hardware described as "configured to" perform a particular function may additionally or alternatively be described as "adapted to" perform that function and/or "operable to" perform that function.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the disclosed concepts, which may be practiced without some or all of these details. In other instances, details of known devices and/or processes have been omitted so as not to unnecessarily obscure the present disclosure. While some concepts will be described in conjunction with specific examples, it will be understood that these examples are not intended to be limiting.

The systems and methods described herein are suitable for heat transfer systems that use a cooling medium that includes a liquid component and a gas component. The cooling medium circulates through a fluid circulation system that includes a heat exchange section in thermal contact with the heat-generating electrical component. Accordingly, the cooling medium absorbs energy from the electrical component to maintain the electrical component within a desired temperature range.

In some embodiments, the electrical component of the heat transfer system is an electrochemical cell comprising one or more electrochemical cells. For example, in some embodiments, the electrical component is a battery pack including a plurality of batteries. In other embodiments, the electrical component is another type of electrochemical cell, such as a fuel cell. Furthermore, in other embodiments, the heat transfer system includes another type of electrical component, such as a motor or computer.

In some embodiments, the heat transfer system is part of a vehicle. For example, in some embodiments, the heat transfer system is associated with an electrochemical cell and/or motor in an automobile, truck, locomotive, ship, or aircraft. In other embodiments, the heat transfer system is part of a stationary system (such as a power storage or power generation system). Further, in other embodiments, the heat transfer system is part of another system that includes heat-generating electrical components.

The use of a cooling medium that includes both a liquid component and a gas component may provide several advantages. For example, the inclusion of a gaseous component as part of the cooling medium reduces the weight of the cooling medium circulated through the fluid circulation system. As a result, the overall heat transfer system may have a reduced weight compared to conventional heat transfer systems. This weight reduction may be advantageous in various types of systems. For example, a vehicle using large electrical components (such as a battery or motor) may obtain performance advantages by having a reduced weight of the heat transfer system. The reduced weight of the cooling medium and heat transfer system may be beneficial by reducing the overall weight of the vehicle, thereby improving drivability or efficiency. Alternatively, the reduction in weight of the cooling medium and the heat transfer system may allow the vehicle to add additional beneficial components while maintaining the overall weight of the vehicle. For example, with a reduction in the weight of the cooling medium, additional battery cells may be added while maintaining the weight of the battery pack.

In addition to vehicles, there are other examples in which weight reduction may be advantageous. For example, the location of the heat transfer system may make weight savings beneficial. For example, in elevated locations (such as electrical systems or wind turbines at the top of a building), weight reduction is advantageous for the structural integrity of the support structure.

Referring to the drawings, FIG. 1 shows a heat transfer system 100, the heat transfer system 100 comprising an electrochemical cell 110, the electrochemical cell 110 comprising an electrochemical cell 112. The heat transfer system 100 further includes a fluid circulation system 120, the fluid circulation system 120 including one or more fluid paths for circulating the cooling medium 102, the cooling medium 102 disposed within the fluid circulation system 120 and dispersed throughout the fluid paths. The fluid circulation system 120 includes a heat exchange section 142, the heat exchange section 142 being in thermal contact with the electrochemical cells 110 such that heat generated within the electrochemical cells 110 may be transferred to the cooling medium 102 within the fluid circulation system 120. Within the heat exchange section 142 of the fluid circulation system 120, the cooling medium 102 includes two phases, including a liquid component and a gaseous component.

During operation of the electrochemical cell 110, when current is delivered to the electrochemical cell 112 or current is drawn from the electrochemical cell 112, some energy may be converted to heat within the electrochemical cell 112 or an adjacent electrochemical cell 112. As a result, the electrochemical cell 112 may rise in temperature. The temperature difference between the electrochemical cells 112 and the cooling medium 102 within the heat exchange section 142 may cause energy to dissipate from the electrochemical cells 112 to the cooling medium 102. Likewise, the cooling medium 102 adjacent to other electrochemical cells 112 of the electrochemical cell 110 may similarly absorb heat from other corresponding electrochemical cells 112.

The heat transfer system 100 may also include a pump 122 configured to circulate the cooling medium 102 through the fluid circulation system 120. In some embodiments, as in the embodiment shown in fig. 1, the fluid circulation system 120 may be in the form of a loop, with a pump 122 disposed in the loop to circulate all of the cooling medium 102 around the loop of the fluid circulation system 120. In other embodiments, as described below in various embodiments, the pump 122 may have a different configuration and operate to circulate the cooling medium 102 in another manner.

As used herein, the term pump includes any device that uses energy to move a fluid. For example, the pump may be formed by any actuator or mechanism that moves a fluid (such as a rotary pump, a piston pump, or other pump). Moreover, in other embodiments, the heat transfer system 100 may be configured without a pump. For example, in some embodiments, the cooling medium 102 may circulate through the fluid circulation system 120 due to convection and temperature changes, such as by thermosiphon.

In some embodiments, the heat transfer system 100 may also include a heat exchanger 124 within the fluid circulation system 120. Heat exchanger 124 may be configured to remove energy absorbed from electrochemical cell 110 within heat exchange section 142 of fluid circulation system 120 from cooling medium 102. To facilitate cooling of the cooling medium 102 within the heat exchanger 124, another fluid may pass through the heat exchanger 124 to absorb heat from the cooling medium 102. The heat exchanger may be constructed as a parallel flow heat exchanger, a counter flow heat exchanger or a cross flow heat exchanger. As an example, in some embodiments, the heat exchanger may be a radiator and the second fluid for cooling the cooling medium 102 may be air. In other embodiments, the second fluid may be a liquid coolant that is cooled in a further heat exchanger. In some embodiments, heat exchanger 124 may include intervening passages that hold cooling medium 102 and a second fluid. In other embodiments, the heat exchanger may have a simpler construction, such as a first plate having passages for holding the cooling medium 102 and a second plate having passages for holding the second fluid. Other configurations are also possible.

Moreover, in other embodiments, the heat transfer system 100 may include other structures to absorb energy from the cooling medium 102 in addition to or in lieu of a heat exchanger. For example, in some embodiments, a heat sink may be used to reduce the temperature of the cooling medium 102.

In some embodiments, the electrochemical cell may include a plurality of electrochemical cells. For example, in the embodiment shown in fig. 1, the electrochemical cell 110 includes a number of electrochemical cells 112 electrically connected and disposed in a single housing 114 forming the electrochemical cell 110. As an example, in some embodiments, the electrochemical cell 110 may be a battery including a plurality of battery cells disposed within a battery housing. In other embodiments, the electrochemical cell 110 may comprise a single electrochemical cell, such as a single battery or other type of cell.

In various embodiments of the heat transfer system 100, the ratio of the gaseous component to the liquid component of the cooling medium 102 may vary within a range of values. Furthermore, as explained in more detail below, the ratio of gas components to liquid components may vary within the fluid circulation system 100. For example, in some embodiments, the gas component may form a higher percentage of the cooling medium 102 in certain regions of the fluid circulation system 120 than in other regions of the fluid circulation system 120.

In some embodiments, within the heat exchange section 142 of the fluid circulation system 120, the gas component may form at least 50% by volume of the cooling medium 102. Further, in some embodiments, the gaseous component may form at least 75% of the cooling medium 102 or at least 80% of the cooling medium or at least 90% of the cooling medium by volume. Furthermore, the weight of the gaseous components of the cooling medium is not quite substantial. Thus, replacement of the liquid with the gaseous component of the cooling medium results in a substantial direct reduction in weight of the system. Thus, a system in which 80% of the cooling medium is gaseous may have a weight reduction of about 80% compared to a system in which the cooling medium is entirely liquid. Of course, in other embodiments, the gas component may form a smaller percentage of the cooling medium within the heat exchange section 142 of the fluid circulation system 120.

In some embodiments, at least a portion of the liquid component and the gas component of the cooling medium form a foam within the heat exchange section of the fluid circulation system. As used herein, the term foam includes bubbles of gas dispersed in a liquid. In some embodiments, the foam stabilizes for at least 10 seconds, such as at least 30 seconds, such as at least 1 minute. In some embodiments, the foam moves jointly through the heat exchange section such that the velocity of the gas component in the heat exchange section is substantially equal to the velocity of the liquid component in the heat exchange section. In other words, in some embodiments, the bubbles of gas and the liquid surrounding the bubbles move substantially together through the fluid circulation system. For example, in some embodiments, the velocity of the liquid component through the center of a conduit of the fluid circulation system is at least 80% of the velocity of the gas component through the center of the same conduit. In other embodiments, the bubbles of gas component move through the liquid component and the liquid component moves at a slower rate.

In some embodiments, the liquid component of the cooling medium includes one or more liquid coolants. For example, the liquid component of the cooling medium may include a water-based coolant. Such coolants may include ethylene glycol or other additives. Likewise, the liquid component of the cooling medium may alternatively be an oil-based coolant. As will be appreciated by one of ordinary skill in the art, the liquid coolant of the cooling medium may include various mixtures of components.

In some embodiments, the liquid component of the cooling medium includes at least one of a surfactant and a foam inhibitor. For example, in some embodiments, the liquid component of the cooling medium includes a concentrate of both surfactant and suds suppressor to affect various characteristics of the cooling medium, such as bubble size, viscosity, and other characteristics.

In some embodiments, the heat exchange section of the fluid circulation system includes a fluid path that extends through the electrochemical cell such that the cooling medium is in direct contact with the electrochemical cell. Fig. 2 shows a more detailed embodiment of an electrochemical cell having such a configuration. The electrochemical cell shown in fig. 2 is configured as a battery pack 210 comprising a plurality of battery cells 212. However, it is also possible to have cells of the same construction as shown in fig. 2 with other types of electrochemical cells.

The battery pack 210 may include a housing 214 that holds a battery cell 212 and a fluid conduit 244 of the fluid circulation system 220. In addition, the battery pack 210 may also include electrical terminals 216 on the exterior of the housing 214, the electrical terminals 216 for connecting the battery pack 210 to a power source or electrical load. The battery pack 210 may further include electrical connectors 218 that electrically connect the battery cells 212 within the battery pack 210. The electrical connection 216 may connect the battery cells 212 in series, parallel, or a combination, such as a number of battery cells 212 connected in series to form a group, and the groups of battery cells connected in parallel.

The electrical connection may include any conductive structure to transfer electrical current from one battery-type cell to another battery-type cell. For example, the electrical connection may include tabs that act as terminals for each of the battery cells, the tabs being connected to one another by wires or conductive rods. Other electrical connections are also possible.

In some embodiments, the electrical connection 218 may be contained within the fluid circulation system 220. For example, as shown in fig. 2, electrical connections 218 between battery cells 212 in the battery pack 210 may be positioned within a fluid circulation system 220 such that the cooling medium 202 surrounds the electrical connections 218. Such a configuration allows any heat generated by the flow of current through the electrical connection 218 to dissipate into the cooling medium 202.

In some embodiments, the battery cell 212 is a pouch cell. For example, the housing of the battery cell 212 may be in the form of a pouch formed of a flexible material such as foil. Tabs forming terminals for the battery cells 212 may be connected to electrodes within the housing and extend from the housing for electrical connection to other battery cells 212. In addition, the tabs may be sealed where they pass through the battery housing. In other embodiments, the battery-type cell may be a prismatic cell or a cylindrical cell.

In some embodiments, the liquid component of the cooling medium 202 may be a dielectric. Accordingly, conductive portions (such as terminals) of the battery cells 212 may be in direct fluid communication with the cooling medium 202 without compromising the performance of the battery cells 212. As used herein, the term dielectric includes various dielectric substances known in the art and that may be suitably used in the systems and methods described herein. For example, embodiments of the first fluid can include aliphatic compounds (e.g., C14-C50 alkyl compounds, C14-C50 alkenyl compounds, C14-C50 alkynyl compounds, polyolefins (such as poly-alpha-olefins)), aliphatic oxygenates (e.g., ketones, ethers, esters, or amides), aromatic compounds (e.g., dialkylbenzenes (such as diethylbenzene), cyclohexylbenzene, 1-alkylnaphthalenes, 2-alkylnaphthalenes, dibenzyltoluenes, and alkylated biphenyls), aromatic oxygenates (e.g., ketones, ethers, esters, or amides), silicones (e.g., silicone oils and silicate esters), halogenated hydrocarbons, and hydrohaloethers, and any combination thereof. In some embodiments, the cooling medium 202 may have a dielectric constant or relative permittivity less than 6. Further, in some embodiments, the liquid component of the cooling medium may be a liquid dielectric medium having a mineral oil base. Other liquid dielectrics including synthetic fluids are also possible for use as the liquid component of the cooling medium.

In some embodiments, the fluid conduit 244 of the heat exchange section 242 of the fluid circulation system 220 is at least partially defined by the housing of the battery cell 212. For example, as shown in fig. 2, the first fluid conduit 244 is defined by the housing of the battery cell 212 on either side of the first fluid conduit 244. The use of the housing of the battery cell 212 to define the portion of the boundary of the first fluid conduit 244 causes the cooling medium 202 to be in fluid contact with the battery cell 212, which facilitates heat transfer between the battery cell 212 and the cooling medium 202 within the first fluid conduit 244. In addition to the housing of the battery cell 212, the fluid conduit 244 within the battery pack 210 may also be defined by the housing 214 of the battery pack 210 or by other components.

In some embodiments, the heat exchange section of the fluid circulation system includes a fluid conduit extending through the electrochemical cell that is electrically isolated from the electrochemical cell. Fig. 3 shows a more detailed embodiment of an electrochemical cell having such a configuration. Like the electrochemical cell of fig. 2, the electrochemical cell shown in fig. 3 is configured as a battery pack 310 that includes a plurality of battery cells 312. However, it is also possible to have cells of the same construction as shown in fig. 3 with other types of electrochemical cells.

The battery pack 310 shown in fig. 3 may include a housing 314 holding a battery cell 312 and a plurality of enclosed fluid conduits 344 of a fluid circulation system 320. For example, fluid conduit 344 through battery pack 310 may be defined by a closed conduit wall 346 (such as a pipe). Thus, the battery cell 312 is isolated from the cooling medium 302 inside the fluid conduit 344. Likewise, the internal electrical connections 318 between the battery cells 312 and the external connections 316 of the battery pack 310 are also isolated from the cooling medium 302. The conduit wall 346 may be formed of a thermally conductive material (such as metal) so that energy from the battery-type cells may be readily transferred to the cooling medium 302 disposed in the fluid circulation system 320.

Furthermore, in other embodiments, the fluid circulation system may be located entirely outside of the housing of the electrochemical cell. For example, in some embodiments, the heat exchange section of the fluid circulation system may be positioned adjacent to the electrochemical cell, but outside of the electrochemical cell. Still further, in some embodiments, the housing of the electrochemical cell may provide a passageway through the middle of the cell to allow the cooling medium to flow near different areas of the electrochemical cell.

Fig. 4 illustrates another embodiment of a heat transfer system according to the present disclosure. The heat transfer system 400 illustrated in fig. 4 is part of an electric vehicle 490 and includes electrochemical cells in the form of a battery pack 410. However, similar heat transfer systems may also include other types of electrochemical cells, and may be included in other types of machines or devices as previously described.

The battery pack 410 shown in fig. 4 includes a plurality of battery cells 412 held in a housing 414. The heat transfer system 400 includes a fluid circulation system 420, the fluid circulation system 420 containing a cooling medium 402 that includes both a liquid component and a gas component. In particular, the liquid component and the gaseous component of the cooling medium 402 are mixed within the heat exchange section 442 of the fluid circulation system 420.

The fluid circulation system 420 includes a passageway that extends freely through the battery pack 410 such that the cooling medium 402 is in direct contact with the battery cells 412. In particular, heat exchange section 442 of fluid circulation system 420 is formed in a region of battery pack 410 where cooling medium 402 is in direct contact with battery cells 412.

The fluid circulation system 420 of the embodiment of the heat transfer system 400 shown in fig. 4 has a main circuit 440 including a heat exchange section 442 and a return path 448 to recover the cooling medium 402. As shown in fig. 4, the liquid component of the cooling medium 402 may be limited to the primary loop 440. In contrast, the gaseous component of the cooling medium 402 may be introduced upstream of the heat exchange section 442 and then extracted from the main circuit 440 downstream of the heat exchange section 442. Thus, while the cooling medium 402 may include both liquid components and gaseous components within the heat exchange section 442, the two components may be separated in other portions of the fluid circulation system. For example, the fluid circulation system 420 of the heat transfer system 400 shown in fig. 4 may include a gas inlet 464 into the main circuit 440 positioned upstream of the heat exchange section 442 and a gas outlet 466 from the main circuit 440 downstream of the heat exchange section.

In some embodiments, the gas inlet is one of a plurality of gas inlets disposed upstream of the heat exchange section. For example, the main circuit 440 may include a plurality of gas inlets 464 coupled to the gas lines 462 to inject the gas component of the cooling medium 402 at various locations of the main circuit 440 upstream of the heat exchange section 442. The use of multiple gas inlets 464 may allow for injection of the gas component into main circuit 440 at a location that allows for dispersion of the gas component throughout battery pack 410. For example, one or more gas components may be positioned to inject bubbles of the gas component between each of the battery cells 412. In addition, the use of multiple gas inlets 464 may also help disperse the gas component within the liquid component. For example, the use of multiple gas inlets 464 may help form smaller bubbles of the gas component within the liquid component of the cooling medium 402.

In some embodiments, the fluid circulation system 420 may also include a gas inlet 464 for a gas component of the cooling medium 402 within the heat exchange section 442 of the primary loop 440. For example, in some embodiments, the gaseous component of the cooling medium 402 may be injected into the main circuit 440 of the fluid circulation system both upstream of the heat exchange section 442 and within the heat exchange section 442. The use of gas inlets 464 within the heat exchange section 442 may help facilitate gas distribution throughout the heat exchange section 442. For example, in some embodiments, the gas inlet 464 may be placed within the heat exchange section at a location where gas bubbles will not travel or where gas bubbles may otherwise become stagnant, such as in corners. Alternatively, in some embodiments, the fluid circulation system 420 may include a gas inlet 464 located only within the heat exchange section 442 of the primary loop 440.

In some embodiments, the gas inlet may be disposed below the electrochemical cell and the gas outlet may be disposed above the electrochemical cell such that buoyancy of the gas component causes the gas component to rise through the electrochemical cell. For example, the gas inlet 464 of the fluid circulation system 420 of the embodiment shown in fig. 4 is positioned under the battery cells 412 of the battery pack 410. Thus, when the gaseous component of the cooling medium is injected into the main circuit 440, gaseous bubbles will form and rise through the liquid component. For example, the gas component may be delivered into the main circuit from gas line 462 using pump 422. Due to the buoyancy of the gas bubbles, the gas bubbles will continue to rise until they reach the surface of the liquid component. A gas outlet 466 positioned at the top of battery pack 410 and above the surface of the liquid component of cooling medium 402 may be used to collect the gas component that has been injected into main circuit 440.

Further, in some embodiments, the rise of gas bubbles may cause the liquid component of cooling medium 402 to also rise through battery pack 410. The liquid component may then drain back toward the bottom of battery pack 410 through return path 448 due to gravity. Thus, in some embodiments, the gas pump 422 is sufficient to circulate the gaseous component of the cooling medium 402 around the fluid circulation system 420. In other embodiments, the heat transfer system 400 may include both liquid and gas pumps to move the different components of the cooling medium 402 as they separate.

In embodiments of the heat transfer system, the flow of bubbles of the gaseous component through the liquid component of the cooling medium may cause turbulence and increased mixing of the cooling medium within the fluid circulation system. This increased mixing may increase heat transfer from the electrochemical cell to the cooling medium, thereby increasing the efficiency of the heat transfer system. This increase in efficiency of heat transfer between the electrochemical cells and the cooling medium may make the heat transfer system of the present disclosure attractive even in situations where weight reduction is not an important consideration.

In some embodiments, the fluid circulation system of the system may include a secondary loop extending from the gas outlet to the gas inlet to recirculate the gas components around the fluid circulation system. For example, heat transfer system 400 may include a secondary loop 460 extending from the top of battery pack 410 where the gas component is collected through gas outlet 466 to a gas line 462 where the gas component is injected into the liquid component of cooling medium 402 through gas inlet 464. The secondary loop 460 may further include a gas pump 422 to drive the gas composition into the primary loop 440. The use of secondary loop 460 may allow the gas component to be recirculated through the battery pack rather than being vented.

In other embodiments, the gaseous component of the cooling medium may be air captured from the surrounding environment. Thus, such embodiments may include an air inlet upstream of the gas inlet to the primary circuit, and the gas outlet may be vented from the system without the need to utilize a secondary circuit to recycle air. Further, in some embodiments, an air intake may be connected to one or more filters to dry the air and remove undesirable contaminants. Furthermore, in other embodiments, the gas component of the fluid circulation system may be a stored or generated gas that is not recovered, but is allowed to escape into the surrounding environment.

The heat transfer system 400 may also include a heat exchanger 424 to absorb energy from the cooling medium 402. For example, battery pack 410 is positioned on heat exchanger 424 in the form of a plate, with coolant passing through the heat exchanger. The location of the heat exchanger 424 at the bottom of the battery pack allows the liquid component of the cooling medium 402 that has been recirculated through the return path 448 to be cooled before it is driven back through the heat exchange section 442 of the fluid circulation system 420, where it cools the battery cells 412.

In some embodiments, the heat transfer system may include a controller configured to perform a method of operating the heat transfer system as described below. For example, the heat transfer system 400 illustrated in fig. 4 includes a controller 480, the controller 480 configured to send control signals to the gas pump 422 to operate the gas pump to circulate the cooling medium 402 through the fluid circulation system 420.

The controller 480 may include a non-transitory computer readable medium having stored thereon program instructions for performing the methods of the present disclosure. In some embodiments, the controller 480 may include at least one memory 482, at least one processor 484, and/or a network interface 486. Additionally or alternatively, in other embodiments, the controller 480 may comprise a different type of computing device operable to execute program instructions. For example, in some embodiments, the controller may comprise an Application Specific Integrated Circuit (ASIC) or a Field Programmable Gate Array (FPGA) that performs the operations of the processor.

While controller 480 of heat transfer system 400 may be physically disposed within electric vehicle 490 (as shown in fig. 4), in other embodiments, at least some portion of controller 480 may be physically separate from the rest of electric vehicle 490. For example, in some embodiments, one or more portions of the controller 480 may be remote from the electric vehicle 490 and communicate with the rest of the electric vehicle via the network interface 486. Further, in some embodiments, the controller 480 may be a client device, i.e., a device that is actively operated by a user, while in other embodiments, the controller 480 may be a server device, e.g., a device that provides computing services to a client device. Moreover, other types of computing platforms are possible in embodiments of the present disclosure.

The memory 482 may be computer usable memory such as Random Access Memory (RAM), read Only Memory (ROM), non-volatile memory (such as flash memory), solid state drives, hard drives, optical memory devices, and/or magnetic storage devices.

The processor 484 of the controller 480 includes a computer processing element, such as a Central Processing Unit (CPU), a Digital Signal Processor (DSP), or a network processor. In some embodiments, the processor 484 may include a register memory to temporarily store instructions being executed and corresponding data and/or a cache to temporarily store instructions being executed. In certain embodiments, the memory 482 stores program instructions executable by the processor 484 for performing the methods and operations of the present disclosure, as described herein.

The network interface 486 provides a communication medium, such as, but not limited to, a digital communication medium and/or an analog communication medium, between the controller 480 and other computing systems or devices. In some embodiments, the network interface may operate via a wireless connection (such as IEEE 802.11 or bluetooth), while in other embodiments, the network interface 486 may operate via a physical wired connection (such as an ethernet connection). Moreover, in other embodiments, the network interface 486 may communicate using another convention.

In some embodiments, the controller 480 may receive sensor values from various sensors and adapt control signals sent to the gas pump 422 based on the values from the sensors. For example, the controller 480 may receive a temperature value from the temperature sensor 488 and send a control signal to the pump 422 using a feedback loop based on the value received from the temperature sensor 488. Further, the controller 480 may receive a value corresponding to a current flowing into the battery pack 410 or flowing out of the battery pack 410 from the ammeter, and adjust the control signal based on the value received from the ammeter.

While the embodiment shown in fig. 4 provides direct contact between the cooling medium 402 and the battery-type cells 412, the use of a fluid circulation system having a gas inlet and a gas outlet may also be utilized in embodiments in which the fluid circulation system is isolated from the electrochemical cells. Such an embodiment is shown, for example, in fig. 5. The heat transfer system 500 shown in fig. 5 includes an electrochemical cell 510 having a plurality of electrochemical cells 512. The system also includes a fluid circulation system 520, the fluid circulation system 520 including a plurality of conduits 544 defined by discrete conduit walls 546 extending through the electrochemical cells 510. Accordingly, the cooling medium 502 is maintained in the fluid conduit 544 and is in thermal communication with the electrochemical cells 512 within the heat exchange section 542 of the fluid circulation system 520.

The liquid component of the cooling medium 502 shown in fig. 5 is contained within the main circuit 540 of the fluid circulation system 520. On the other hand, the gaseous components of the cooling medium 502 are injected into the primary circuit 540 through a plurality of gas inlets 564 below the electrochemical cells 512. At the top of the electrochemical cell 510, gas is collected in the gas outlet 566 and recirculated through the secondary loop 560 by the gas pump 522. Likewise, the liquid component of the cooling medium 502 returns to the bottom of the electrochemical cell 510 through return path 548 where it is cooled by the heat exchanger 524 before being driven back through the heat exchange section 542 of the fluid circulation system 520 by gas bubbles injected through the gas inlet 564.

Similar to fig. 4, the electrochemical cell 510 shown in fig. 5 may be a battery pack or other type of cell, and the device 590 may be an electric vehicle or another machine or device. In addition, heat transfer system 500 may also include a controller 580, controller 580 having any of the features and configurations described above with respect to the controller shown in fig. 4, such as a processor 582, a memory 584, and a communication interface 586.

In some embodiments of the heat transfer system, the cooling medium includes a liquid component and a gas component throughout the fluid circulation system. Such a system is shown, for example, in fig. 6. The heat transfer system 600 includes a fluid circulation system 620 in which both the liquid component and the gas component of the cooling medium 602 are dispersed throughout the system. While the heat transfer system 600 illustrated in fig. 6 is part of an electric vehicle 690 and includes electrochemical cells in the form of a battery pack 610, similar heat transfer systems may also include other types of electrochemical cells and may be included in other types of machines or devices as previously described.

The heat transfer system 600 may include a pump 622, the pump 622 configured to propel a cooling medium including both a liquid component and a gas component around the fluid circulation system 620. For example, as described above, the cooling medium 602 may be in the form of foam that is driven by the pump 622 through the path of the fluid circulation system 620. Further, in some embodiments, pump 622 may assist in generating foam by separating the gas component into discrete bubbles within the liquid component.

In addition, the heat transfer system 600 may also include a heat exchanger 624, the heat exchanger 624 reducing the temperature of the cooling medium 602 as the cooling medium 602 circulates through the fluid circulation system 620. As shown in fig. 6, the heat exchanger 624 may be positioned downstream of the pump, or the heat exchanger 624 may be positioned upstream of the pump (as shown in fig. 7). Further, in some embodiments, the heat exchanger may include several sections positioned both upstream and downstream of the pump.

Similar to the electrochemical cell shown in fig. 4, the electrochemical cell 610 shown in fig. 6 may be a battery or other type of cell, and the device 690 may be an electric vehicle or another machine or device. Further, the heat transfer system 600 may also include a controller 680, the controller 680 having any of the features and configurations described above with respect to the controller shown in fig. 4, such as a processor 682, a memory 684, and a communication interface 686.

While the embodiment shown in fig. 6 includes the entire fluid circulation system 620 disposed within the housing 614 of the battery pack 612, in other embodiments, portions of the fluid circulation system may be disposed outside of the housing. For example, in some embodiments (such as in fig. 7, described below), one or both of the pump and the heat exchanger may be disposed outside of the housing so as to be separate from the battery pack. In such examples, the battery pack may have one or more inlets and outlets for introducing and removing cooling medium therefrom.

While the embodiment shown in fig. 6 provides direct contact between the cooling medium 602 and the battery-type cells 612, in embodiments in which the fluid circulation system is isolated from the electrochemical cells, the use of a system in which the gas component and the liquid component are distributed throughout the fluid circulation system may also be utilized. Such an embodiment is shown, for example, in fig. 7. The heat transfer system 700 shown in fig. 7 includes an electrochemical cell 710 having a plurality of electrochemical cells 712. The system also has a fluid circulation system 720 and a heat exchanger 724, the fluid circulation system 720 including a pump 722 that circulates a cooling medium through the electrochemical cells 710. The fluid circulation system 720 has a plurality of conduits 744 formed by discrete conduit walls 746 extending through the electrochemical cells 710 such that the cooling medium 702 held in the fluid conduits 744 is in thermal communication with the electrochemical cells 712 within the heat exchange section 742 of the fluid circulation system 720.

In some embodiments, the heat transfer system 700 may include a mixer configured to promote bubble formation within the cooling medium. For example, in some embodiments, the fluid circulation system 720 may include a reservoir 728 in which the cooling medium 702 is collected. The mixer 726 may be associated with a reservoir 728 and operates to form discrete bubbles of the gaseous component in the cooling medium 702. In some embodiments, as shown in fig. 7, mixer 726 may be configured as a pump. In other embodiments, the mixer 726 may be configured as a stirrer that includes an impeller or a shaking member. Other configurations are also possible. Furthermore, while the embodiment shown in fig. 7 includes a reservoir 728 connected to the mixer 726, in other embodiments the mixer may be positioned in another location, such as within a conduit of a fluid circulation system.

While the heat exchanger 724, pump 722, reservoir 728, and mixer 726 are all shown external to the housing 714 of the electrochemical cell 710, in other embodiments some or all of these components may be part of the electrochemical cell and disposed within the housing.

Similar to the electrochemical cell shown in fig. 4, the electrochemical cell 710 shown in fig. 7 may be a battery pack or other type of cell, and the device 790 may be an electric vehicle or another machine or device. Further, heat transfer system 700 may also include a controller 780, controller 780 having any of the features and configurations described above with respect to the controller shown in fig. 4, such as processor 782, memory 784, and communication interface 786.

In another aspect, the present disclosure provides an electric vehicle including a heat transfer system including a battery pack including a plurality of battery cells. The heat transfer system also includes a fluid circulation system including a heat exchange section in thermal contact with the battery pack. A cooling medium is disposed in the fluid circulation system and, within the heat exchange section of the fluid circulation system, the cooling medium includes a mixture including a liquid component and a gas component. The pump is configured to circulate a cooling medium through the fluid circulation system. The heat transfer system may include any of the various features of the heat transfer system described above.

In another aspect, the present disclosure provides a heat transfer system comprising: an electrochemical cell comprising an electrochemical cell; and a fluid circulation system. The fluid circulation system includes a primary circuit extending through the electrochemical cell. The fluid circulation system further comprises a secondary circuit extending from a gas outlet from the primary circuit downstream of the electrochemical cell to a gas inlet into the primary circuit upstream of the electrochemical cell.

In another aspect, the present disclosure provides a method of cooling an electrochemical cell. Fig. 8 illustrates an embodiment of such a method 800. In various embodiments, the method 800 may be performed using any of the heat transfer systems 100, 400, 500, 600, or 700 shown in fig. 1, 4, 5, 6, and 7, or alternative configurations thereof. As shown at block 802, the method 800 may involve providing a heat exchange section of a fluid circulation system in thermal contact with an electrochemical cell comprising an electrochemical cell. Further, as shown at block 804, the method may also involve circulating a cooling medium through the fluid circulation system to transfer energy from the electrochemical cell to the cooling medium, wherein the cooling medium includes a liquid component and a gas component within a heat transfer section of the fluid circulation system.

In some embodiments of the method 800, circulating the cooling medium at block 804 may maintain the gaseous component of the cooling medium at a ratio of at least 50% by volume within the heat exchange section of the fluid circulation system. For example, in an embodiment utilizing the heat exchange system 400 shown in fig. 4, the controller 480 may send an operating signal to the gas pump 422 to inject a sufficient volume of the gas component into the main circuit 440 of the fluid circulation system 420 to maintain the gas component of the cooling medium 402 at a rate of at least 50% by volume. Likewise, an embodiment utilizing the heat exchange system 500 shown in fig. 5 may operate similarly. Further, utilizing the embodiment of the heat exchange system 600 shown in fig. 6 may include using a controller 680 to send a signal to the pump 622 to generate a desired foam property of the cooling medium 602 and move the cooling medium 602 through the electrochemical cell 610 in a manner that maintains a majority of the cooling medium as a gas within the heat exchange section of the fluid circulation system 620. Further, in embodiments utilizing the heat exchange system 700 shown in fig. 7, the controller 780 may send control signals to the mixer 726 or pump 722 to generate the desired foam properties of the cooling medium 702 and move the cooling medium 702 through the electrochemical cells 710 in a manner that maintains a majority of the cooling medium as a gas within the heat exchange section of the fluid circulation system 720.

The various features and functions of the disclosed systems, devices, and methods are described above with reference to the accompanying drawings. In the drawings, like numerals typically identify like components unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope of the invention being indicated by the following claims.

Claims

1. A heat transfer system, comprising:

an electrochemical cell comprising an electrochemical cell;

a cooling medium disposed in the fluid circulation system, wherein within the heat exchange section of the fluid circulation system, the cooling medium comprises a mixture comprising a liquid component and a gas component; and

a pump configured to circulate the cooling medium through the fluid circulation system.

2. The heat transfer system of claim 1, wherein within the heat exchange section of the fluid circulation system, the gas component forms at least 50% by volume of the cooling medium, or,

wherein at least a portion of the liquid and gaseous components of the cooling medium form a foam within the heat exchange section of the fluid circulation system.

3. A heat transfer system according to claim 1 or claim 2, wherein the heat exchange section of the fluid circulation system comprises a fluid path extending through the electrochemical cell such that the cooling medium is in direct contact with the electrochemical cell.

4. A heat transfer system according to any one of claims 1 to 3, wherein the liquid component of the cooling medium comprises at least one of a surfactant and a foam inhibitor.

5. The heat transfer system of any of claims 1-4, wherein the fluid circulation system comprises:

a main circuit comprising the heat exchange section, wherein the liquid component of the cooling medium is confined to the main circuit,

a gas inlet in the main circuit upstream of the heat exchange section; and

a gas outlet in the main circuit downstream of the heat exchange section.

6. The heat transfer system of claim 5, wherein the gas inlet is one of a plurality of gas inlets disposed upstream of the heat exchange section, or,

wherein the gas inlet is disposed below the electrochemical cell and the gas outlet is disposed above the electrochemical cell such that buoyancy of the gas component causes the gas component to rise through the electrochemical cell or,

wherein the fluid circulation system further comprises a secondary circuit extending from the gas outlet to the gas inlet for recirculating the gas component around the fluid circulation system.

7. The heat transfer system of any of claims 1-6, wherein the cooling medium comprises the liquid component and the gas component throughout the fluid circulation system.

8. The heat transfer system of claim 7, wherein the pump is configured to circulate the liquid component and gaseous component of the cooling medium as a mixture around the fluid circulation system.

9. The heat transfer system of claim 7, further comprising a mixer configured to promote bubble formation within the cooling medium.

10. A method of cooling an electrochemical cell, the method comprising:

circulating a cooling medium through the fluid circulation system to transfer energy from the electrochemical cell to the cooling medium, wherein the cooling medium comprises a liquid component and a gas component within the heat transfer section of the fluid circulation system.

11. The method of claim 10, wherein circulating the cooling medium maintains the gaseous component of the cooling medium in a ratio of at least 50% by volume within the heat exchange section of the fluid circulation system, or,

wherein circulating the cooling medium comprises maintaining the cooling medium in the form of foam throughout the fluid circulation system, optionally wherein circulating the cooling medium comprises circulating the foam by a pump.

12. The method of claim 10 or claim 11, wherein the fluid circulation system comprises a main circuit comprising the heat exchange section,

wherein the liquid component of the cooling medium is confined to the main circuit and,

wherein circulating the cooling medium comprises injecting the gaseous component into the primary loop.

13. The method of claim 12, wherein injecting the gas component into the main circuit drives the liquid component through the fluid circulation system.

14. The method of claim 13, wherein the gas component is injected into the main circuit at a location below the electrochemical cell such that buoyancy of the gas component causes the gas component to rise through the electrochemical cell.

15. The method of claim 14, further comprising collecting the gas component through an outlet of the main circuit.